This
page
is
part
of
FHIR
STU
3
(v3.0.1)
in
it's
permanent
home
(it
will
always
be
available
at
this
URL).
It
has
been
superceded
by
R4
.
For
a
full
list
of
available
versions,
see
the
Directory
of
published
versions
.

No
particular
relationship
between
the
concepts
can
be
assumed,
except
what
can
be
determined
by
inspection
of
the
definitions
of
the
elements
(possible
reasons
to
use
this:
importing
from
a
source
where
this
is
not
defined,
or
where
various
parts
of
the
hierarchy
have
different
meanings)
meanings).

A
hierarchy
where
the
child
concepts
have
an
IS-A
relationship
with
the
parents
-
that
is,
all
the
properties
of
the
parent
are
also
true
for
its
child
concepts
concepts.
Not
that
is-a
is
a
property
of
the
concepts,
so
additional
subsumption
relationships
may
be
defined
using
properties
or
the
[subsumes](extension-codesystem-subsumes.html)
extension.

Child
concepts
in
the
hierarchy
may
have
only
one
parent,
and
there
is
a
presumption
that
the
code
system
is
a
"closed
world"
meaning
all
things
must
be
in
the
hierarchy.
This
results
in
concepts
such
as
"not
otherwise
classified."
classified.".

A
few
code
lists
that
FHIR
defines
are
hierarchical
-
each
code
is
assigned
a
level.
In
this
scheme,
some
codes
For
value
sets,
levels
are
under
other
codes,
and
imply
that
the
mostly
used
to
organize
codes
for
user
convenience,
but
may
follow
code
they
are
under
also
applies
system
hierarchy
-
see
Code
System
for
further
information

Source

The
source
of
the
definition
of
the
code
(when
the
value
set
draws
in
codes
defined
elsewhere)

Code

The
code
(used
as
the
code
in
the
resource
instance).
If
the
code
is
in
italics,
this
indicates
that
the
code
is
not
selectable
('Abstract')

Display

The
display
(used
in
the
display
element
of
a
Coding
).
If
there
is
no
display,
implementers
should
not
simply
display
the
code,
but
map
the
concept
into
their
application